Emergency buoyancy generating apparatus

ABSTRACT

A NEGATIVELY BUOYANT BODY (E.G. DAMAGED MARINE VESSEL, AIRCRAFT DOWNED AT SEA, PRACTICE TORPEDO, PRACTICE GUIDED MISSILE ETC.) IS RENDERED WATER-BUOYANT ON COMMAND BY GENERATING POLYMER FOAM REACTION MIX IN A   FLEXIBLE BAG, WHICH IS STORED PRIOR TO USE IN A COLLAPSED FOLDED CONDITION, AND WHICH EXPANDS AFTER FILLING WITH POLYMER FOAM MIX TO PROVIDE THE DESIRED BUOYANCY.

Nov. 2, 1971 D. A. HOLTER 3,616,775

EMERGENCY BUOYANCY GENERATING APPARATUS Filed July 14, 1969 2 Sheets-Sheet 1 DELA/VE A. HOL TEA lNl/E/VTOR BY LVWAM Agent Nov. 2, 1971 HQLTER 3,616,175

EMERGENCY BUOYANCY GENERATING APPARATUS Filed July 14, 1969 2 Sheets-Sheet 2 Q SOLENO/D DELANE AHOL 75/? lNVE/VTOR Agent United States Patent O 3,616,775 EMERGENCY BUOYANCY GENERATING APPARATUS Delane A. Holter, Manhattan Beach, Calif., assignor to The Upjohn Company, Kalamazoo, Mich. Filed July 14, 1969, Ser. No. 841,494 Int. Cl. B63c 7/12 US. Cl. 11454 6 Claims ABSTRACT OF THE DISCLOSURE A negatively buoyant body (e.g. damaged marine vessel, aircraft downed at sea, practice torpedo, practice guided missile etc.) is rendered water-buoyant on command by generating polymer foam reaction mix in a flexible bag, which is stored prior to use in a collapsed folded condition, and which expands after filling with polymer foam mix to provide the desired buoyancy.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to flotation apparatus and is more particularly concerned with apparatus for rendering buoyant a negative buoyant body such as a torpedo, an aircraft fuselage, a damaged water-borne vessel, a dummy guided missile and the like.

(2) Description of the prior art A number of methods have been described in the art for providing emergency flotation to aid in the recovery of negatively buoyant bodies such as practice torpedoes, aircraft which have been forced to descend on water in emergencies, marine vessels holed below the water line, etc. Illustratively, it has been suggested to recover practice torpedoes by providing means of jettisoning ballast at the end of a practice run (see US. Pat. 3,153,394) or to fill collapsed flexible containers with gas carried in appropriate containers (see US. Pat. 2,949,877) or generated in situ by reaction with water (see US. Pat. 3,175,525). The first type of method is not efficient and the latter two methods suffer the disadvantage that the flexible gas filled container is susceptible to rupture by contact with sharp objects such as rocks, reefs and the like.

It has also been suggested that marine vessels can be rendered virtually unsinkable by filling bulk heads and like cavities with rigid polymer foam such as polyurethane foam. Such means of providing flotation has the disadvantage that the polyurethane foam so introduced occupies a vast amount of space which could otherwise be profitably used. It has also been suggested that sunken vessels can be recovered by generating polymer foam within the compartments in the sunken vessel until sufficient polymer foam has been produced to render the submerged vessel buoyant. This procedure, while efficient, has the obvious disadvantage that it has only been applied after the event, i.e. submersion of the marine vessel has taken place, and has not been used hitherto to prevent the event occurring.

We have now found that the various disadvantages inherent in the process hitherto used for providing necessary buoyancy for negatively buoyant bodies can be overcome. We have also found that it is possible to provide the necessary buoyancy in a wide variety of different negatively buoyant bodies using essentially the same buoyancy providing device which will now be described herein.

SUMMARY OF THE INVENTION This invention in its broadest aspect comprises: a buoyancy-generating device adapted to be disposed within a 3,616,775 Patented Nov. 2., 1971 ice negatively, or potentially negatively, buoyant body, said buoyancy-generating device comprising, in combination:

said buoyancy-generating device being so disposed within the negatively buoyant body that said inflatable collapsed flexible bag is free to be inflated by the foam generated by said polymer foam reaction components.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a perspective plan view of an illustrative embodiment of a portable buoyancy generating device according to the invention.

FIGS. 2 and 2a show a cross-sectional view of the illustrative embodiment of FIG. 1.

FIG. 3 shows a partially cutaway view of a buoyancy generating device used in combination with a practice torpedo in accordance with the invention.

FIG. 4 is a schematic representation of control means for actuating a buoyancy-generating device of the invention.

DETAILED DESCRIPTION OF THE INVENTION As discussed above, the apparatus for providing water buoyancy in accordance with the invention can be used in a number of different applications but the essential features of the device used to generate the buoyancy are the same in all applications. Depending on the size of the body to be rendered buoyant and the capacity of the device, in terms of the amount of buoyancy which a single device can provide, it is possible to employ one or more such devices, acting independently or in unison, in any particular body to be rendered buoyant.

The essential features of the buoyancy-generating device are as follows. A plurality of storage containers, i.e. two or more such containers, is employed to store polymer foam reaction components which, when brought together at the required moment, will interact to produce the desired polymer foam. The nature of the components in the storage containers depends upon the particular polymer foam employed. Any of the polymer foam forming systems known in the art can be employed.

For example, the various storage containers can contain the components necessary to produce a polyurethane foam. Such foams generally require at least two reaction components which are brought together at the required time. One of said reaction components comprises a polyisocyanate such as polymethylene polyphenyl isocyanate, toluene diisocyanate (generally a mixture of the 2,4- and 2,6-toluene diisocyanates) and the like. The second reaction component generally comprises a mixture of a polyol, a catalyst for the reaction between the isocyanate groups of the polyisocyanate, and the active hydrogen containing groups of said polyol, as well as surfactants and other optional additives. In some instances the catalyst and the polyol are maintained in separate containers but obviously it is more efiicient to employ the minimum number of containers in order to save storage space.

The various reaction components are stored in the storage containers in association with a propellant gas such as those commonly employed in the aerosol dispensing art. Preferably the gas used as propellant in the storage containers is, or includes, that which is to be used as blowing agent in the cellular foam mix to be generated. Thus the propellant is preferably an inert gas such as dry nitrogen or a mixture thereof with a halogenated aliphatic hydrocarbon having a boiling point below approximately 110 C. and preferably below about 50 C. such as chlorotrifluoromethane, trichloromonofluoromethane, dichlorodifluoromethane, and related materials. For a detailed discussion of the procedures and components for the preparation of polyurethane foams, see, for example, Saunders et al., Polyurethanes, Chemistry and Technology, Part II, 1964, Interscience, New York.

If desired, each of said storage containers is provided with a pressure gauge so that a quick visual check can be made from time to time, to ensure that pressure necessary for actuation is being maintained in said containers. Said containers are adapted to be readily detachable and replaceable as the necessity arises.

Each of said storage containers is provided with appropriate valves which allow the components of the various containers to be dispensed in any desired proportions into a foam mixing chamber. The latter comprises a hollow chamber advantageously of cylindrical shape having inlet ports and exit ports. The inlet ports are situated advantageously at one end of said chamber and the exit ports at the opposite end. The foam reaction ingredients can be dispensed directly to one or more inlet ports or alternatively can be dispensed into a common conduit which leads to the inlet port of the foam mixing chamber. The foam mixing chamber can be provided with baflie means which serves to ensure adequate mixing of the foam reaction components before they are expelled from the foam mixing chamber.

Said baflle means may take any of the foams con-ventionally employed in the art. Preferably said baffle means is constructed in such a manner that the path which the foam reaction mix is caused to follow is tortuous. For example, said baflle means can comprise a series of discs mounted on an axis within the foam reaction chamber. Each of said discs is mounted approximately at right angles to the longitudinal axis of the mixing chamber and the discs preferably extend to the peripheries of the walls of said mixing chamber except for a small cutout portion in the outer edge of each disc. The cutout portion on any one disc is located at approximately 180 radially from the corresponding aperture in neighboring discs thereby providing maximum mixing of the foam reaction mix as it passes from one end of the mixing chamber to the other.

Attached to the exit port of the foam mixing chamber is a flexible bag which, apart from its mouth which is attached in sealing engagement with the exit port, is complete fluid proof. Advantageously, the flexible bag is constructed of a thin polymer sheet material, such as polyethylene or polypropylene of the required strength, although materials such as rubber, waterproof paper, and the like, can be employed. The capacity of said flexible bag can be adjusted according to the volume of polymer foam to be generated. The flexible bag is stored in folded condition.

The various components of the buoyancy generating device can be mounted in appropriately cooperating positions in any suitable housing. Where one or a plurality of such devices are to be disposed throughout a waterborne vessel for emergency flotation purposes said housing can be made portable so that the device or devices can be transferred readily to any desired location. Alternatively, when the buoyancy-generating device is to be installed permanently in a negatively buoyant body, it is preferably mounted in a compartment specially provided within the body to be rendered buoyant. Such compartments will be described in more detail in discussing specific embodiments of this invention herein below.

The foam generating device of the invention can be actuated in a number of ways depending upon the circum- 4 stances in which it is to be used. For example, when said device is provided in portable form and is to be operated manually, said device is actuated simply by manual turning of the appropriate valve or valves on the storage containers thereby setting in motion the foam generating reaction. Alternatively, said device can be provided with mechanically controlled means for actuating the foam generating reaction and, if desired, said mechanical actuating means can be triggered by remote control as will be discussed in relation to specific embodiments set forth below.

The apparatus of the invention will now be further illustrated by reference to a number of specific embodiments.

In FIG. 1 there appears a perspective view of a portable foam generating device. The outer container 10 is pro vided with a hinged lid 12 equipped with a latch 14, 14a. Within the container 10 are disposed two cylindrical storage containers 16 which are retained in place thereinby means of bracket 18 and cooperating hoop fasteners 20. The cylindrical containers 16 are connected by conduits 22 to a three-way valve 24, the third outlet from which is joined by conduit 26 to one end of a mixing chamber 28. The other end of said mixing chamber is secured to, and leads into, an opening in an inflatable flexible bag 30 which is shown in collapsed, folded form in FIG. 1 and is disposed within a compartment formed by barrier 32 in one end of the container 10.

FIG. 2 shows a cross-sectional plan view of the embodiment of FIG. 1 taken through the plane 2-2. In FIG. 2, the storage containers 16 are shown detchably mounted on the conduits 22 by means of coupling units 34. One end of each of the conduits 22 extends into the corresponding container 16 to a point approximating the lower end of said container 16. The other end of each of said conduits 22 connects the storage containers 16 to the 3-way valve 24 which in turn is connected by conduit 26 to the entry port 36 of the mixing chamber 28. The latter is cylindrical and is provided with an exit port 38 at the end thereof remote from the entry port 36. The exit port 38 has attached thereto, securely and in sealing engagement therewith, the sole opening 40 in the collapsed flexible bag 30. In the particular embodiment of FIG. 2, the mouth 40 of the flexible bag 30 is held in sealing engagement with the outside of the exit port 38 by means of the ring clip 42. The mode of attachment is shown in the enlarged cross-sectional view of FIG. 2a. The mixing chamber 28 is provided with a bafiie 44; the latter compiises a series of discs 48 mounted on an axle 46 which is disposed longitudinally within the chamber 28. Said baffle discs 48 are each provided with an aperture 50 at one edge thereof, the apertures 50 in alternate discs 48 being disposed on opposite sides of the axle 46 so that fluid passing through said chamber 28 is constrained to follow a tortuous path.

In operating the particular embodiment of a portable buoyancy generating device shown in FIGS. 1 and 2, the polymer foam reaction components are charged to storage containers 16 and are stored therein under pressure using an inert gas such as nitrogen or a mixture of nitrogen and a volatile liquid, such as a highly halogenated alkane, as hereinbefore defined, having a boiling point below about C. and preferably below about 50 C., which is to be employed as blowing agent in preparing the polymer foam. The portable buoyancy generating device is actuated manually by turning the 3-way valve 24 in the appropriate direction so that each of the conduits 22, 22, and 26 is rendered interconnecting. The contents of the storage containers 16 are thereby released and are passed via the conduits 22, 22, and 26 into the mixing chamber 28 wherein mixing occurs prior to entry of the foam reaction mix into the flexible plastic bag 30. Expansion of the foam mix within the flexible bag 30 causes inflation of the latter. The inflation of the flexible bag 30 is facilitated by removing the bulk of the latter from the confines of the compartment in which it is housed for storage. If desired, the end wall 52 of the outer container 10 can be made detachable, either completely or hingably, so that free expansion of the flexible bag 30 is possible. The capacity of the flexible bag 30 and the volume to which the polymer foam mix will expand are advantageously adjusted so that they are approximately equal,

The outer container of the device shown in FIGS. 1 and 2 can be provided with exterior securing means, such as a toggle (not shown), for attaching said container 10 to an appropriate location in the body to which it is desired to impart buoyancy, e.g. to the gunwale or the deck of a small boat. The device illustrated in FIGS. 1 and 2, or a plurality of such devices, can be carried aboard the small boat as required and actuated by hand to provide the necessary buoyancy to maintain the boat afloat if an emergency requires this, e.g. if the boat becomes holed or waterlogged.

As will be readily appreciated by one skilled in the art, the particular mode of construction of the device shown in FIGS. 1 and 2 can be varied in numerous ways without departing from the scope of the present invention. For example, the 3-way valve 24 can be replaced by individual valves in each of the conduits 22. Actuation of the two valves simultaneously would then be necessary to achieve the desired actuation of the buoyancy generating device. Similarly, more than two storage containers 16 can be provided if more than two components are necessary or desirable to provide the polymer foam reaction mix.

In FIG. 3 there is shown another particular embodiment of the invention in which the buoyancy-generating device is shown installed in the nose of a practice torpedo. Said device is so positioned in a compartment of the torpedo 54 that the flexible bag 30 in stored collapsed condition is immediately adjacent a detachable plate 56 in the wall of the torpedo. The plate 56 can be attached by means of a s ring loaded hinge so that the plate 56 is retained in sealing engagement with the surrounding wall of the torpedo but is thrust open by the pressure exerted from the inside by the inflating of the flexible bag 30 after actuation of the buoyancy generating device. Alternatively, the plate 56 can be provided with means for its removal by explosion of a small detonating charge at the time the buoyancy device is actuated.

In the case of the particular embodiment shown in FIG. 3 the valve 24 obviously cannot be actuated manually at the end of practice runs of the torpedo. Numerous methods of actuating the device can be adopted. One such mode of operation is illustrated in FIG. 4 wherein the valve arm 58 is pivotally attached at one end thereof to the rod 60 via pivot 62. The rod 60 is attached to a solenoid 64 which latter can be actuated, at any desired time, by a circuit which is closed in response to a clockwork device, or to a radio signal transmitted from a control center on board a surface vessel. Thus, at the time it is desired to recover the practice torpedo, actuation of the solenoid causes lateral movement of rod 60, turning of the valve arm 58 and opening of the valve 24. The sequence of events which follows thereafter is the same as that described in connection with the embodiment shown in FIGS. 1 and 2 save that the bulk of the inflatable bag 30 passes through the hatch from which cover plate 56 has been removed and is inflated with foam to provide the desired buoyancy and cause the practice torpedo to rise to the surface of the ocean.

In a modification of the above embodiment the flexible bag is adapted so that, upon inflation, it becomes detached from the end of mixing chamber 28 but is still secured to the hull of the torpedo by a line of sufficient length to enable the inflated flexible bag to rise to the surface of the water and serve as a marker buoy indicating the position of the submerged torpedo.

The above described means for recovery of a practice torpedo by means of a buoyancy-generating device of the invention can be readily adapted to the recovery of a practice airborne missile which descends into the ocean, or other body of water, at the end of its flight. The mode of operation of the device of the invention for this purpose parallels that described above for the recovery of a practice torpedo.

[In yet other embodiments of the invention, the buoyancy-generating device of the invention can be installed in one or more compartments in the exterior walls of an aircraft fuselage. The method of installation corresponds to that shown in the torpedo recovery device of FIG. 3, the flexible bag 30 in stored condition being located next to a detachable plate so that the bag is free to be inflated on actuation of the device. The actuation of all such devices in the aircraft fuselage can be made in emergency either by manual turning of the various valves 24 or by simultaneous actuation from a central control point, illustratively using an actuating means such as that shown in FIG. 4.

Alternatively, where a plurality of buoyancy-generating devices are to be dispersed throughout a vessel such as a ship or aircraft, it is possible to store the foam generating reactants at a central location within the vessel and, by means of appropriate conduits, to dispense foam generating mix to flexible bags located in various places through the vessel. It is found that foam generating mix can be transported through supply tubes of up to ft. in length in such an arrangement. The construction and mode of operation of such an embodiment is essentially the same as that illustrated in FIGS. 2 and 3 except that the length of conduit separating the storage containers from the mixing chamber is extended substantially.

As will be obvious to one skilled in the art, the size of the device, and hence the amount of flotation provided, can be varied in accordance with the particular application for which the device is to be employed. In general each one pound by weight of polymer foam generating components in the cylinders 16 will provide a minimum of 30 pounds flotation factor. This represents an efficiency far in excess of any emergency flotation device hitherto provided.

The flotation generating devices of the invention can be adapted, if desired, for use as fire extinguishers, particularly to provide means of smothering fires which occur in confined spaces. Thus, by constructing the flexible bag component of the device of the invention from a flame resistant material, the devices of the invention can be employed to extinguish fires in compartments of marine vessels, aircraft and the like as well as to extinguish fires in confined locations in domestic buildings and the like.

While the novel apparatus of the invention has been described above with reference to certain specific embodiments thereof, it is to be clearly understood that these embodiments have been given for purposes of illustration only and are not intended to be limiting. The scope of the invention is bounded only by the scope of the claims which are set out hereafter.

What is claimed is:

1. A manually portable emergency buoyancy-generating device comprising, in combination:

(i) a manually portable housing enclosure;

(ii) a plurality of storage containers mounted within said housing and having stored therein the reaction components for producing a polyurethane polymer foam;

(iii) a foam reactant mixing chamber mounted within said housing and having inlet and exit ports;

(iv) means within said housing for dispensing, on command, the foam reaction components to the inlet port of said foam mixing chamber;

(v) an inflatable collapsed flexible bag disposed within said housing and having a mouth securely attached to the exit port of said foam reactant mixing chamber and adapted to receive substantially unexpanded polyurethane polymer foam reaction mix from said chamber; and

(vi) opening means to permit the bulk of said flexible bag, after inflation, to pass to the outside of said portable housing.

2. A portable buoyancy-generating device according to claim 1, having means on said portable housing for detachably securing said device to a negatively, or potentially negatively, buoyant body.

3. A portable buoyancy-generating device according to claim 1, wherein said foam reactant mixing chamber has a baffie disposed between said inlet and exit ports; said baflle comprising a plurality of discs mounted on a central axle, the faces of said discs being disposed substantially at right angles to the direction of flow of the foam reaction mixture, said discs each having an aperture in the perimeter thereof to permit passage of foam reaction mixture therethrough.

4. A portable buoyancy-generating device according to claim 1, wherein said flexible bag is constructed of a flame resistant material.

5. A portable buoyancy-generating device according to claim 1 wherein said storage containers are detachably mounted within said housing.

6. A manually portable emergency buoyancy-generating device which comprises, a manually portable housing having a hinged lid, said housing enclosing;

(i) first and second storage containers detachably mounted within said housing and having stored therein, under propellant gas pressure, the reaction components for producing a polyurethane foam;

(ii) individual conduits for transferring said reaction components from said storage containers to a single Valve means located Within said housing;

(iii) said valve means upon activation serving to release foam reaction components simultaneously from said storage containers via said conduits and to discharge the mixed components via a single conduit into a foam reactant mixing chamber;

(iv) said mixing chamber having an entry port, an exit port and a baflle interposed between said entry and exit ports;

(v) said bafile comprising a plurality of discs mounted on a central axle, the faces of said discs being disposed substantially at right angles to the direction of flow of the foam reaction mixture, said discs each having an aperture in the perimeter thereof to permit passage of foam reaction mixture therethrough; 1

(vi) an inflatable, collapsed, flexible bag having a mouth securely attached to the exit port of said foam reactant mixing chamber and adapted to receive substantially unexpanded polyurethane polymer foam reaction mix from said chamber; said bag being so disposed within the portable housing in relation to the hinged lid thereof as to permit release of the bulk of said flexible bag, after inflation to the outside of said housing via the opened lid.

References Cited UNITED STATES PATENTS 1,306,011 6 /1919 Horak 9-327 X 1,818,697 8/1931 Adam-s 244107 2,852,072 9/1958 Alfery et al. 137-62411 2,918,030 12/1959 Bagnall 114-64 2,949,877 8/ 1960 Newburn et al.

2,989,938 6/1961 Patterson 114-50 3,269,342 8/1966 Sobok l14-5 3,372,899 3/ 1968 McPherson 2'5130 MILTON BUCHLER, Primary Examiner G. W. OCONNOR, Assistant Examiner US. Cl. X.R. 9--327 

